Valve mechanism for rock drills



June 23, 1931. F. M. SLATER I VALVE MECHANISM FOR ROCK DRILLS Filed Jan. 12, 1929 V/ Y 30$ v a INVENTOR. I5 4? Mcf'lafev. BY a HIS A TORNEY.

Patented June 23, 1931 UNITED STATES T W .LFICE EREn M. SLATER, E EAs'roN, PENNSYLVANIA,- AssitenoRro NeERsoLL-RANn COM- rANY, 0E JERSEY crrY, NEW- JERSEY, A coRroRArmE OF NEW JERSEY VALVE. MECHANISM EoR RQQGK DRILLS Application meg January 12, 1929.- Serial to. 331,961.

'"This inventionrelates to rock drills but more particularly to a valve mechanism for rock drills of the fluid actuated type. 7

7 One object of the invention is to insure an early cut off during the admission of pressure fluid to the cylinder sot-hat the hammer piston may be impelled throughout a portion of its stroke by the expansive force of the pressure fluid.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawings illustrating the invention andin which similar reference charactersrefer to similar parts,

Figure 1 is a sectional elevation of a portion of a rock drill equipped with valve mechanism constructed in accordance with the practice of the invention,

, Figure 2 is a transverse view taken through I Figure 1 on the line 22 looking in the direction indicated by the arrows, c

Figure 3 is a sectional elevation taken through Figure 2 on the line 3-3 looking in the direction indicated by the arrows, and

Figure 41 is a similar View taken through Figure 2 on the line H. v -V Referring more particularly to the drawings, Arepresents a cylinder of a rock drill having a pistonchamber B in which is dis 3c posed-a reciprocatory hammer piston C.

The cylinder A has a free exhaust port D which is controlled by the head E of the piston C. On the forward end of the piston C is a reduced eXtensionF which is guided by a bore G of a front cylinder washer H inserted in the front end of the piston chamber B to form a closure therefor.

In the rearward end of the enlarged bore J for the reception of a valve mechanism including a rotation ratchet L.

the bore J; The rotation ratchet L may be of a well known type having the usual introverted teeth O which act as abutments for spring pressed pawls P carried by the head Q of a rifle bar R. The rifle bar R extends rotatably-through thevalve chest K and is cylinder A is an.

chest designated generally by K and rotation fluted for engagement with the piston C ina well known manner. v i

In the illustration shown the rotation ratchet L seats on the valve chest K and in turn serves as a seat for a back head S which forms a closure for the rearward end of the cylinder A. V

Among other functions the back head S serves as a housing for a throttle valve T which controls the admission of pressure fluid into the drill. The throttle valve T is of the rotarytype and accordingly has a central chamber U which may be in constant communication with a source of pressure fluid through a connection (not shown) In the side of the throttle valve T is a port V intended to afford communication between the chamber U and a passage WV in the back head S leading to a supply reservoir X, also 7 in the back head S. V The valve chest K comprises in this instancea pair of plates Y and Z. The plate Z serves as a closure for the rearward end of the piston chamber B and the plate Y is disposed between the plate Z and the rotation ratchet L andthe-head Q of the rifle bar for which it'fjorms a' seat.

The adjacent surfaces of the plates Y and Z are recessed to form a valve chamber?) comprising in this instance a reduced portion 0 and an enlarged portion cl. In the-plate Y and adjacent the enlarged portion 8:? of the valve chamber is an annular groove 6 into which pressure fluid may constantly flow from 'the supply reservoir through supply passages f located in this instance in the rotation ratchet'L andthe plate Yf V V Inlet passages g and 71, are" provided for conveying the pressure fluid from i the valve chamber 5 tothe ends of the piston chamber.

Both inlet passages g and h'leadfrom the reduced portion 0 of the valve chamber; the

inlet passage 1 leading to the rearward end of the piston chamber B andthe inlet passage h to the forward end of the piston chamber B.

The distribution of pressure fluid to the ends of the piston chamber is controlled" a valve j of the oscillatory plate type-having a fulcrum k on its transversemedian line wher-eon the valve" y is adapted to rock and on* inlet passage 71 Preferably the valve is only of sufficiently smaller size than the reduced portion of the valve chamber 6 so that the valvejmay have a running fit thereln. In other words, the sides of the valve bear slidably against the adjacent sidesof reduced portion 0 of the valve chamber;

been the practice to rely largely upon the suction of the pressure -fiuid .createdon the raised wings of the valveto assist in closing the valve. Other forces of course also act in proper sequence against the valve for tilting it,;as forinstance, thecompression created in the ends of the pistonchamber and which compression acts-against the valve to assist the suction created by the pressure fluid to throw the valve. In the prior structures,

however, the tilting of the valve does not occur until the piston head E uncovers the exhaust port .to exhaust the pressure fluid utilized foractuatingthe piston to the atmosphere. This causes a decided drop in pressure forwardly of the valve and enablesthe forces acting thereagainst to reverse it.

lVhile the prior device operated satisfactori-1y in most respects it has been found,

however, that bydelaying movement of the valve until the exhaust port is uncovered a considerable amount of pressure fluidflows directly from the sourcebfxsupply to the atmosphere WlthQLllTClOlDg any useful work.

:The present inventioncontemplates over comlngthis wastage of pressure fluid and to use the pressure fluid exp ansively for impelling the piston C, that is,.it contemplates the cutting off of the supply of pressure fluid to the piston chamber before the pistoniiG'places the active side of the piston chamber B in shoulders q and T which serve in this instance as the ends or bounding surfaces of thereduced'portions c of the valve chamber. T he shoulderslag and rare sospaced with respect to each 7 other that when the adjacent wings of thevalve j -are seated'the shoulders will be insubstantially slidableengagementwith the cooperating surfacesjer edges of the valve 3'' i The height of the shoulders g and 1* may vary with the requirements of immediate conditions, but it has been found in practice that the most practicalheightisthat in whiclnwhen the valve, occupies .ga' mean position, that is, when itoccupiesa position in rwhich it lies perpendiculanto the axis of thedrill, the edgespr ends ofthe wings 0,

and p sligh tlyoverlie the respective shoulders 'wherewiththeycooperate to cut off communication between the enlarged portion (Z of l miting position.

the valve and may be such height that only a relatively small shoulder or surface 6 rep I V p p V H r 1 mains near the rearward end of the valve for Heretofore in valve-structures of the type to which the present invention pertains ithas to live pressure fluid to accelerate the actionof the valve, recesses u and o are formed in the plate Z beneath the wings 0 and p respectively, and ports 10 and a; are formed in these wings for introducing pressure fluid into the recesses when the wings are seated;

The following isla description of the operation of the device: Withthe valve j in the position illustrated in Figure 1, in which the inlet passage h is covered by the wing 99 of the valve, pressure fluid will flow over the edge of the wing 0,thencethrough the inlet passage 9 into the rearward end of the piston B to impel the piston C forwardly to deliver its blow against the working implement (not shown). hen the head Eof the piston C overruns the exhaust port D the air in the front end of the piston chamber 13 will be compressed and will flow through the" inlet passage h to act against of the wing 19 of the valve g V p As the piston advances in a'forwardly di-' rection the compression pressure will rapidly increase until it reaches a value which, to-

gether with theslightsuctio'n created onthe edge of the wing-0 of the valve, will start the valve to move in thedirection of its other 7 This occurs just before the head E of the piston uncovers the exhaust port D'and therefore only a short period "be? fore the piston delivers its Yblowl 1' During onlya small portion ef-the movement of the valve jwill there be any flow ofpressure fluid between the edge ofthe wing; 0'- andythe shoulder 11; As-the :va'lve approaches a=positionin which it lies substantially perpendicular to the axis of the drill the edge of the wing 0 will move into the plane of the shoulder alto cut ofi the flow ofp ressure into the forward suface the rearwardendl of the piston chamber;

a portionof the subsequent movement of the valve the edge of the wing 5 will also lie in the plane of the cooperating sheulder Duringthisportion of-the movement of the valve there will be no admission of pressure.

Vvhilethevalve isinthis'position and during blow of the piston against the working implement the compression in the front end of the piston chamber will have reached its maximum pressure and this compression will then act against the wing p to rock said wing ber B to impelthe piston G rearwardly,

During this movement of the piston and when the exhaust port D is covered thereby, the air in the rearward end of the piston chamber B will be compressed to act against the forward surface of the wing 0. The compression thus acting against the wing 0 of the valve, together with the suction created by the pres sure fluid flowing over the raised end of the wing will unseat the wing 0 and will lower the wing p into the plane of the shoulder Q before the wing 0 has been rocked out of the plane of the shoulder r. This position of the valve will be assumed before the head E of the piston C uncovers the exhaust port D and the piston C will then be actuated rearwardly by the force of the expanding pressure fluid in the front end of the piston chamber to point where it will uncover the exhaust port- D. As

the piston G moves rearwardly the compres-V sion in the rearward end of the piston chamber will of course increase in pressure and such compression will then again return the valve 7' to its initial position.

The present invention has been found to be highly advantageous in structures of the type described. Foremost of its advantages are the considerable saving in the matter of pressure fluid consumption due to the early out off ofpressure fluid to the piston chamher, and to the heavy blow which is delivered by the hammer piston to the working implement as a result of this control of the pressure fluid admission.

I claim: 7

1. In a fluid actuated i'ockdi'ill, the combination of a cylinder and a piston, an exhaust port in the cylinder controlled by the piston, a valve chamber, inlet passages leading from the valve chamber to the cylinder, an

oscillatory plate valve in the valve chamber controlling the inlet passages, and means in the valve chamber cooperating with the valve to cut oil" the flow of pressure fluid to both ends of the cylinder during a portion of each opening movement of the valve.

V 2. In a fluid actuated rock drill, the combination of a cylinder and a piston, an exhaust port in the cylinder controlled by the p1ston, a valve chamber, inlet passages leading from the valve chamber to the cylinder an oscillatory plate valve in the valve chamher controlling the inlet passages, and means in the valve chamber cooperating with the valve in an intermediate position of saidvalve to cut oflthe flow of pressure fluid'to'both ends of the cylinder; 1

In a fluid actuated rockdrill, the 'combination of a cylinder and a piston, an exhause port in the cylinder controlled by the piston, a valve chamber, inlet passages lead-' ing from the valve chamber to the cylinder,

an oscillatory plate valve in the valve chamber controlling the inlet passages, and means in the valve chamber cooperating with the side of the valve to cut-off the flow of pres? sure fluid to one end of the cylinder prior to the admission of pressure fluid to the other end of the cylinder. Y Y

4. In a fluid. actuated rock drill,*the combination ofa cylinder and a piston, an exjhaust port in the cylinder controlled by the piston, a valve chamber, inlet passages leading from the valve chamber to'the cylinder, and an oscillatory plate valve in the valve chamber to control the inlet passages and cooperating with the bounding surface of the valve chamber to cut off the flow of pressure fluid to one end of the cylinderpriorto the admission of pressure fluid to the other end of the cylinder.

5. In a fluid actuated rock drill, the com- V bination of a cylinder and a piston an exhaust port in the cylinder controlled by the piston, a valve chamber comprising an enlarged portion and a reduced portion, inlet passages leading from the reduced portion to the cylinder, and an oscillatory plate valve in the reduced portion to control the inlet passages and cooperating with the bounding surface of the reduced portion to cut ed the flow of pressure fluid to-one end of the cylinder prior to the admission of pressure fluid to the other end of the cylinder."

6. Ina fluid actuated rock drill, the combination'of, a cylinderja'nd a piston, an exhaustjportin the cylinder controlled by the pi-ston, 'a valve chamber comprising an enlarged portion and a reduced portion, inlet passages leading from the reduced'portion to the cylinder, and an oscillatory plate valve having a pair of wings to control the inlet passages, said wings rocking into the enlarged portion to permit the flow of pressure fluid over the wings into the inlet passages and cooperating with the bounding surface of the reduced portion to cut oil the flow of pressure fluid to one inlet passage prior to the admission of pressure fluid to another inlet passage.

7. In a fluid actuated rock drill, the combinationof a cylinder and a piston, aneX- haustport in the cylinder controlled by the piston, a valve chamber having a shoulder to form a reduced portion in the valve chamber, inlet passages leading from the reduced portion to the cylinder, and an oscillatory plate valve in the reduced portion controlling the I sion of pressure inlet passages V and cooperating with 'the shoulder in an'intermediate position of the valve to cut oil the How of pressure fluid to one end of the cylinder prior to theadmisfluid to-the other end of the cylinder.

8. In a fluid-actuated rock drill, the combination of a cylinder and a piston, an eX- haust port in the cylinder controlled by the piston, a valve chamber having a shoulder to form a reduced portion in the valve chamber, inlet passages leading iromthe reduced portion to the cylinder, an oscillatory plate valve in the reduced portion controlling the.

- inlet passages and cooperating with the shoulder in an intermediate position of the valve to cut of: the flow of pressure fluid to one end of thecylinderbeforethe admission of pressure fluid to the other end of the cylinder, and recesses in the sides ofthe valve 3 to insure a maximum admission of pressure fluid into-the cylinder with a minimum lift of the valve. J V i 9. In a fluid actuated rock drill, the combination of a cylinder and a piston therein,

an exhaust port in the. cylinder controlled by the piston, a valve chamber having shoulders on opposite sides thereof to form a reduced portion in the valve chamber, inlet passages leading from the reduced portion to the cylinder, an oscillatory plate valve in the reduced portion having wings to control the inlet passages and cooperating with the shoulders to effect the cut-oil of pressure fluid to one end of the cylinder before. estab lishing communication between the valve chamber and the other end of thecylinder, thereby enabling the piston to be actuated throughout a portion of its stroke by the expansive action of the pressure fluid.

In testimony whereof I have signed this specification. v V

FRED M. SLATER.

CERTIFICATE OF CORRECTION.

Patent No. 1,810,988. Granted June 23, 1931, to

FRED M. SLATER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 4, lines 2 and 3, claim 7, strike out the words "in an intermediate position of the valve"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 4th day of August, A. D. 1931.

Wm. A. Kinnan, (Sea!) Acting Commissioner of Patents. 

